She quit her job. Her car caught on fire. So why was novelist Tracy Chevalier so happy?

An old man on a train once told me that we will make two or three big career changes in our lives. He had been an engineer all his life, and the day he retired he became a swimming coach—though he had never coached anyone and didn't even swim that well.

"Nothing is written in stone," he was saying. "You can change. You're expected to change. Change is good."

I always thought any big changes I made in my life would be carefully thought out—every option analyzed, every angle considered, the pros and cons weighed up before I reached a rational decision. I made the decision that changed my career in a split second, without any conscious thought at all.

I was 30 years old and working in London as an editor of encyclopedias about writers. I wasn't having much fun in my job, but I hung on—I still loved editing books and thought things would eventually improve.

The big change began one morning on top of a double-decker bus that I rode every day to work. I was leafing through the newspaper and came across an article about the MA program in creative writing at the University of East Anglia. It was the first and one of the only graduate programs in creative writing in Britain, and renowned for turning out famous writers.

I read the article, glowingly written by a former student, and thought: Interesting. Then I turned the page and read an article about face cream or a theater review or a political analysis of East-West relations, and thought, That's nice. Nothing really sank in—I hadn't had my coffee yet.

When I walked into the office, my boss came up to me before I'd even taken off my coat or, crucially, had that coffee. To this day I can't remember exactly what she said—something I should have done or shouldn't have done or mustn't do again or ought to have done better. I do remember precisely my response. I looked at her and thought, "Gotta get out of here. I'm gonna do that MA in Creative Writing."

The decision felt immediate, but it must have been brewing inside me, waiting for the right moment to jump out and give me a big shove. Maybe I had reached the conclusion that I'd rather be my own boss than work for other people.

Maybe I had realized that life is short and I didn't want to spend it doing something that no longer made me happy. Or maybe I had finally heard what the old man on the train tried to tell me: Change is good.